Improvement in processes and apparatus for reducing ores



M. LAFLIN.

PRQCESS AND APPARATUS FOR REDUCING DRES.

No. 181,003. Patented Aug.15,1a7e.

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'UNITED STATES PATENT rrrcs MATTHEW LAFLIN, OF CHICAGO, ILLINOIS.

IMPROVEMENT IN PROCESSES AND` APPARATUS FOR REDUCING ORES.

Specification forming part of Letters Patent No. 1S 1,003, dated August 15, 1876; application tiled i l February 8, 1876.

view; Fig. 2,a cross-Seel cess or processesv patented to me on the 22d day ofJuly,1873, and on the 23d day of Manch, 1875 5 and its nature consists in the process and devices hereinafter described and claimed as new. i

The ore to be operated upon is first reduced to a tine or impalpable powder, and alkali should be applied with water to the ore in a suitable pan, in which the material can be made to boil. The boiling is continued until the ore is thoroughly permeated with the alkali-say for ten minutes, more or less. When the materials are boiled down or dried, the pan is covered with a lid, so as to prevent the ore from coming in contact with the air, in order to prevent oxidation and volatilization of the metals. When the material comes to a red heat, remove the lid and stir the co'ntents of the pan until the alkali has neutraL ized the sulphur and such other foreign substances as admit of an alkaline neutralization. If the composition or material tends to slag, sprinklein powdered charcoal and mix At this stage the composition is ready for amalgamation. If the ore is free from lead it can be boiled in Water, with quicksilver mixed with powdered charcoal; or the metals collected can be4 treated by any of the meth- If the ore contains lead it can be worked in a blast-furnace, in which case it may be necessary to slag it in the pan; or the ore can be worked through molten lead by the devices hereinafter described.

In preparingthe alkali for` the pan I use about eighty-seven gallons of caustic soda to a ton of ore. Toprepare `the caustic soda l make it of a strength of 24.0 Baume to one hundred pounds of soda-ash, thoroughly melted or dissolved in Water; add sixty pounds ot' unsl-.iked lime, and boil hard for about ve minutes; then let it settle for about tive hours, and dip out or draw off the clear liquor. Other alkaline solutions, however, may be used ill-place of this, and their preparation will be varied somewhat, according to the alkalies use d, and the character of the ore and amount of sulphur combined therewith, and all of them will vary according to the kind of ore; and for the purpose of the improvements herein described it is not necessary that the ores be roasted in a close vessel or retort, if roasted, and the ores need not be previously roasted at all.

In the drawings, A represents the pan, made of cast-iron, of about three by eight feet in dimension, and eight inches in depth; B, its cover, made of cast or sheet iron, with iianges, so as to it the pan. It is about an eighth of an inch less in diameter or dimension than the pan, in order to prevent sticking by expansion, and is provided with a vent-hole in the top, to which a pipe is attached, which carries off all the evaporation or vaporization into a vessel containing water, which water can be used to boil the next charge. This lid or cover B is provided with a rim, and may be stii'ened with bars to prevent warping and facilitate handling. C is the kettle for the lead-bath, which is made about four feet in diameter, and cylindrical for eighteen inches in its depth, in order that its lid may rise and fall. D is the lid for the lead-bath kettle. This lid is about one-half inch less in diameter than the interior diameter of the kettle, and is provided at its periphery with a close flange, which descends about eight inches. Its interior is provided with a number of teeth or projections placed about halt'an inch apart. These teeth are most conveniently made of wire, cnt to descend to the lower line of the rim, and so placed in the mold as to be cast into its cap or top plate. The cap is provided with a small vent-hole in the top to allow the escape of the air, and when the air has escaped the hole is then stopped by a plug of any suit able description. The lid should weigh, wher.

completed, about seven hundred pounds.

In operation, take the ore hot from the pan A, and put it into the kettle C, containing molten lead, and, if necessary to prevent oxidatiou of the lead, cover it with line charcoal to a sufficient depth to practically exclude the air; then place the lid D in position, and force the ore down into the lead. For a kettle containing three and a half tons ot' lead, as is designed in the kettle shown, a pressure of about six hundred to seven hundred pounds will be required for this. When the ore is down revolve or agitate the lid D, so as to bring all ot' the ore in contact with the lead, first letting the lid remain on the kettle C long enough to become heated before bringing itin contact with the lead. When sufficient time has elapsed, remove the lid D slowly, and reciprocate or revolve it at the same time it is being raised, so as to let the lead settle down out of the ore.

To facilitate the operation of the device a counterbalance or gearing maybe applied. When the lid has been removed, remove the dbris or tailings from the top ot' the lead, leaving about an inch and a halt' to prevent oxidation; then repeat the operation until the lead has absorbed all the metal it can hold. The contents of the kettle then, being bullion, can be separated by any of the ordinary methods.

The process herein described is not only applicable to ores containing gold and silver, but also 'to metals, such as copper, zinc, lead, and others, combining with sulphur.

What I claim as new, and desire to secure by Letters Patent, is as follows:

1. The process of treating ore, which consists in boiling the same, in form of a fine powder, in a solution of caustic alkali, until it is thoroughly permeated, substantially as described.

2. The process ot treating ore, which consists in boiling the same, in form ot' a line powder, in a solution ot'caustic alkali, until it is thoroughly permeated, and the materials boiled down or dried and covered, to prevent oxidation and volatilization, substantially as and for the purpose set forth.

3. The process of treating ore by boiling the same, in form of a tine powder, in a solution of caustic alkali, until it is thoroughly permeated, the materials dried and covered, to prevent oxidation and volatilization, and the materials then agitated until the alkali has neutralized all foreign substances that admit of an alkaline neutralization, substantially as and for the purpose set forth.

4. The lid D, provided with teeth or projections, in combination with the kettle C, containing molten lead, substantially as and for the purpose specified.

5. The pan A, in combination with the lid B, provided with a pipe or tube connected with a water-bath, for holding any metals that may be vaporized, substantially as described.

MATTHEW LAFLIN. Witnesses L. L. BOND. O. W. BOND. 

